The breaks include horticulture-themed vacations around the world, with itineraries in the USA, New Zealand, South Africa, Japan, the Azores, France, Italy and Spain.
RHS director-general Sue Biggs said: "My background is in travel, having led a top long-haul operator for many years. The RHS Garden Holidays brochure combines my two passions, travel and gardening."
The brochure contains 10 holidays, each one accompanied by one of Collette’s tour leaders and some of them also accompanied by an RHS horticulturist such as a curator or specialist in a particular field.
One of the tours is a seven-day break looking at the gardens of the Loire from £1,869. Visits will include: Chateau de Chaumont-sur-Loire's International Garden Festival; the gardens at Plessis Sasnieres; and a private tour of Châteaux de Villandry.
Most expensive is the 13-day Beauty of Japan tour - taking in Tokyo and Kyoto - at £4,999 per person. Visits include Kenroku-en, regarded by many as the finest of all gardens in Japan and translating as "Garden of the Six Sublimities".
Meanwhile "Andalucia - Land of Castles, Palaces & Gardens" lasts nine days, costs from £1,589, and takes in the Generalife Gardens at the Alhambra and visits to Seville’s Maria Luisa Park and the Alcazar accompanied by a local botanist.
"By bringing together our own horticultural expertise with the travel knowledge of Collette Worldwide Holidays, we have been able to create a selection of really inspiring tours," said Biggs.
"With 2013 being the year that our very own RHS Chelsea Flower Show celebrates its centenary, money from the tours is going towards the RHS Chelsea Centenary Appeal to help the RHS fund the next 100 years of gardening."
Collette Worldwide Holidays’ general manager Peter Traynor said: "We know from customer feedback there is great demand for holidays that revolve around specific fields of interest, particularly in the escorted tours market.
"By combining our two respective areas of expertise in travel and gardening, we've been able to create some wonderful itineraries, which we look forward to working together to expand."
The other tours are Portugal's Gardens: featuring the Azores & Lisbon; Gardens & Villas of the Italian Lakes; and the Eternal Gardens of Rome. Holidays outside Europe include New Zealand's Garden Route, the longest at 20 days.
Tours titles Gardens of American History, the Historic Gardens of America's North East, and the Floral Wonders of South Africa round off the holiday list. Visit www.rhsgardenholidays.com